GB 



DEPARTMENT OF THE INTERIOR 
Franklin K. Lane, Secretary 



United States Geological Survey 

George Otis Smith, Director 
WATER-SUPPLY PAPER 450— A 



GEOLOGY AND WATER RESOURCES OF THE 
GILA AND SAN CARLOS VALLEYS 

IN THE 

SAN CARLOS INDIAN RESERVATION, ARIZONA 

BY V^ 

A. T. SCHWENNESEN 



Contributions to tlie hydrology of the United States, 1919 
( Pages 1-27) 

Published November 10. 1919 




WASHINGTON 

GOVERNMENT PRINTING OFFICE 
1919 





nin^ss GB uzs 
Book .Ato Si- ■ 



r^ 



DEPARTMENT OF THE INTERIOR 

Franklin K. Lane, Secretary 

United States Geological Survey 

George Otis Smith, Director 



Water- Supply Paper 450 — A 



GEOLOGY AND WATER RESOURCES OF THE 
GILA AND SAN CARLOS VALLEYS 

IN THE 

SAN CARLOS INDIAN RESERVATION, ARIZONA 

BY 

A. T. SCHWENNESEN 



Contributions to the hydrology of the United States, 1919 
(Pages 1-27) 

Published November 10, 1919 




WASHINGTON 

GOVERNMENT PRINTING OFFICE 
1919 






CXDNTENTS. 



Page. 

Introduction 1 

Physiography and drainage 4 

General features 4 

Gila Basin 5 

San Carlos Basin 5 

Geology 6 

Igneous rocks 6 

Sedimentary rocks 6 

. Pre-Quaternary rocks 6 

Quaternary deposits 7 

General character 7 

Gila conglomerate 7 

Lake beds 8 

Alluvium. ..,., 10 

Quaternary history .' 10 

Classification of lands 10 

Surface water supply 11 

Present irrigation 16 

Shallow ground water 18 

Occurrence and quantity 18 

Quality 19 

Use for irrigation. 23 

Artesian water 23 

Summary and conclusions 26 



ILLUSTRATIONS. 



Plate I. Map of Arizona showing areas covered by reports of the United States 

Geological Survey relating to ground water 2 

II. Geologic map of Gila Basin and parts of San Carlos Basin, San Carlos 

Indian Reservation, Ariz 8 

III. Map of a part of Gila Valley in San Carlos Indian Reservation, Ariz., 

above San Carlos reservoir site, showing classification of lands and 
location of wells and springs, with notes on topography and native 
vegetation 10 

IV. Map of a part of San Carlos Valley in San Carlos Indian Reservation, 

Ariz., above San Carlos reservoir site, showing classification of 
lands and location of wells, with notes on soil, topography, and 

native vegetation 10 

Figure 1. Map of San Carlos Indian Reservation, Ariz., and adjacent regions, 

showing physiographic provinces 2 

2. Generalized view and cross section of Gila Basin, San Carlos Indian 

Reservation, Ariz., showing physiography and geology 3 

" S« or. :-« 



CONTRIBUTIONS TO THE HYDROLOGY OF THE 
UNITED STATES, 1919. 



Nathan C. Grover, Chief Hydraulic Engineer. 



GEOLOGY AND WATER RESOURCES OF THE GILA AND SAN 
CARLOS VALLEYS IN THE SAN CARLOS INDIAN RESERVA- 
TION, ARIZONA. 



By A. T. SCHWENNESEN. 



INTRODUCTION. 

In recent years the Indian farmers in the valleys of Gila and 
San Carlos rivers, in the San Carlos Indian Reservation (PI. I and 
fig. 1), have been seriously handicapped by an inadequate supply of 
water for irrigating their crops. A shortage of water at times when it 
is most needed has tended to discourage those Indians who are 
making an earnest effort to farm and has done much toward neu- 
tralizing the efforts of the reservation officials to interest others in 
agriculture. The water shortage has been due to a lack of water in 
the streams at certain times of the year and to the difficulties of 
keeping diversion dams and ditches in operation on account of wash- 
outs caused by sudden floods in the rivers and by torrents in the 
tributary arroyos during heavy rains. In the river vaUeys many 
tracts of good land now lying idle could be made productive if 
sufficient water were obtainable. An extension of the present 
system to include these lands, however, would be hkely to fail, 
from the same causes that contribute to the inadequacy of the present 
system. 

Several officials of the United States Office of Indians Affairs, who 
are famihar with conditions in the reservation, have suggested the 
use of ground water for irrigation, and in response to these sugges- 
tions the Indian Office requested the United States Geological Survey 
to make an investigation of the ground-water conditions. The 
purpose of this investigation, as expressed in the letter of authoriza- 
tion, was "to determine the feasibility of drill^g for an irrigation 
water supply, the examination to be restricted to land not included 
within the proposed San Carlos reservoir." 

1 



2 CONTRIBUTIONS TO HYDROLOGY OF UNITED STATES, 1919. 

The field work covered a period of three months and was completed 
in December, 1914. Soon after its completion a report was made to 
the Indian Office containing (1) a brief description of the geologic 
conditions which influence the occurrence of ground water in this 



110° 









■■\. 



\ 



< 



\" l l'/- ' r^r '^T^ 



-!■ % '"' «| FOBSSr , ,A»ACHE ":|f , ,>' \ ,J\J^ , 






'ML 



. --— ,» f*^:, 5^ >,.•; '^ =v>'" 










;<=*Fort Apacliej; f 



^'.>;';.^? 






jionimo ' ''''''^)|/i:-P'ji'\'''v"^r0^/;^/<j ( _. -, 






Figure 1.— Map of San Carlos Indian Reservation, Ariz., and adjacent regions, sliowing piiysiographic 

provinces. 

region, (2) a discussion of the available pumping suppHes in the 
Gila and San Carlos valleys, (3) a discussion of the artesian possi- 
bihties, and (4) a summary of conclusions, with certain definite 
recommendations as to the mode of procedure to develop a sufficient 



U. 8. GEOLOr.lCAL PIUVKV 




Area covered by pi 
water-supply p3 

W md 
P /no 



MAP OF ARIZONA SHOWING AREAS COVE 

SURVEY REI 



Digitized by the Internet Archive 
in 2011 with funding from 
The Library of Congress 



http://www.archive.org/details/geologywaterresoOOschw 



V. 8. GEOLOGICAL SURVEV 



WATER-SUPPLY PAPER 450 PLATE I 




Area covered by present Areas covered by other 

v^ater-supply paper bulletins and water-supply papers 

published or in preparation 



M M> OK ARIZONA SHOWING AREAS COVERED BY REPORTS OF THE UNITED STATES GEOLOGICAL 
SURVEY RELATING TO GROUND WATER. 



SAN" CARLOS INDIAN RESERVATION, ARIZ. 3 

ground-water supply and to increase the irrigated acreage in the 
reservation. The work was done under the direction oi O. E. Meinzer, 
geologist in charge of the Survey's investigations relating to ground 
water. 

To determine the available supplies for pumping from wells in the 
river valleys a study was made of the valley sediments with reference 
to their water-bearing capacity. To determine the quality of this 
supply for irrigation water samples were collected from representative 
wells and sent to the University of Arizona for analysis. 

The artesian problem required the mapping of the geologic forma- 
tions in the Gila and San Carlos basins and a study of their structm'e. 
The results are shown in Plate II and figure 2. Before recommending 
the development of either a pumped or artesian water supply it was 







Figure 2.— Generalized view and cross section of Gila Basin, San Carlos Indian Reservation, Ariz., show- 
ing physiography and geology. A, Mountains; B, hilly belts, produced by erosion of older alluvial 
material (6); C, dissected ancient lake bottom; D, valley of Gila River, produced by erosion of lake 
beds (c) and later deposition of alluvium (d); a, pre-Quatemary igneous and sedimentary rocks; 6, Gila 
conglomerate; c, lake beds; A, Recent alluvium. 

important to know whether the amount of arable land in the San 
Carlos and Gila valleys above the proposed reservoir site was sufficient 
to warrant the drilling of deep wells or the construction of pumping 
plants. For this purpose a plane-table map on a scale of 2,000 feet 
to the inch was made of the portions of the San Carlos and Gila 
valleys above the proposed site (Pis. Ill and IV). 

It was originally planned to include the results of this investigation 
in a more comprehensive paper on parts of southeastern Arizona. 
On account of the writer's resignation from the Geological Survey 
and the changes produced by the war the publication of such a paper 
has been indefinitely postponed, and it appears desirable to publish 
the present brief report, not only to make the local data more acces- 
sible but also because of the bearing of these data on the geologic 
history and ancient lakes or other bodies of standing water that have 



4 CONTRIBUTIONS TO HYDROLOGY OF UNITED STATES, 1919. 

been observed in the fill of other parts of Gila Valley, in the fill of 
San Simon and San Pedro valleys, and, with less certainty, in the 
fill of Sulphur Spring and San Bernardino valleys.^ These deposits 
in Gila, San Pedro, and San Simon valleys are no doubt related to 
one another and have an important bearing on the late geologic 
history and also on the water supply of the region. 

Acknowledgments are due to the superintendent of the reservation, 
Mr. A. L. Lawshe, and to others for assistance in conducting the 
field work and for many courtesies; to Mr. C. H. Southworth, engineer 
of the Indian Office, for furnishing water analyses and for extending 
the hospitahty of his camp; and to the University of Arizona and 
Mr. A. E. Vinson, of the university staff, who made analyses of the 
well waters that were collected. 

PHYSIOGRAPHY AND DRAINAGE, 

GENERAL. FEATURES. 

The San Carlos Indian Reservation can be divided into two parts — 
a plateau area, characterized by mountains and lava plateaus, and a 
basin area, characterized by broad intermontane basins or valleys 
underlain by river and lake deposits. 

The plateau area covers most of the northern and eastern parts of 
the reservation, including the Ash Flat and Natanes plateaus. Its 
southern margin is formed by the Gila Range, and its western 
boundary by a line drawn approximately northward from the 
Triplets to the Salt River divide. (See fig. 1.) 

The basin area includes the Gila Basin, an intermontane trough 
traversed by Gila River, which flows westward through the southern 
part of the reservation, and the San Carlos Basin, a similar trough 
traversed by San Carlos River, which flows southward through the 
western part of the reservation to San Carlos, where it discharges 
into the Gila. The basin area is bounded on the south by the 
Turnbull Range, on the west by the eastern ridges of the Mescal, 
Pinal, and Apache mountains, and on the north in part by the Gila 
Range. (See flg. 1.) 

With the exception of a narrow strip of country south of Salt 
River, all of the reservation drains through a gorge which the Gila 
has cut in theMescal Range and which is known as the box canyon. 
The southern part of the reservation, between the Gila and TurnbuU 
ranges, drains directly into Gila River, which crosses the east 
boundary 2 miles west of Geronimo and flows west-northwestward 
for 25 miles to its junction with the San Carlos and thence southwest- 
ward for 10 miles to the southern boundary of the reservation. 

1 Blake, W. P., Lake Quiburis, an ancient Pliocene lake in Arizona: Arizona Univ. Monthly, vol. 4, 
Febraary, 1902. Meinzer, O. E., and Kelton, F. C, Geology and water resources of Sulphur Spring Valley, 
Ariz.: U. S. Geol. Survey Water-Supply Paper 320, pp. 57-62, 1913. Schwennesen, A. T., Ground water 
in San Simon Valley, Ariz, and N. Mex.: U. S. Geol.Survey Water-Supply Paper 425, pp. 1-35,1917. 



SAN CARLOS INDIAN RESERVATION, ARIZ. 5 

A large territory extending from the vicinity of Globe eastward 
nearly to Gila Bonita Creek and northward as far as the Salt River 
divide drains into San Carlos River, which at San Carlos enters the 
Gila from the north. 

GILA BASIN. 

The surface of the Gila Basin can be divided into sharply con- 
trasting belts that run parallel to its axis. (See fig. 2.) 

On the north and south sides of the basin, adjacent to the moun- 
tains, are belts of hilly country which stand higher than the middle 
of the basin and which have evidently been produced by the erosion 
of what were at one time smooth alluvial slopes extending from the 
mountains toward the middle of the basin. Inside these hilly belts 
are belts of lower country which are the remnants of a lake bottom 
that once extended across the axis of the basin. This lake apparently 
came into existence after the alluvial slopes had been considerably 
eroded. As a result of the large amount of sediment deposited in 
the lake its bottom became smooth and had only gentle slopes toward 
the middle of the basin. Although this former lake bottom has 
been eroded since the disappearance of the lake, it still forms a 
strong contrast to the more anciently dissected marginal belts. 

Inside the belts formed by the remnants of the ancient lake bottom 
is the valley of Gila River, which was cut by the river after the lake 
disappeared. The parts of the ancient lake bottom adjacent to the 
river valley have become much dissected, and with reference to the 
valley they form a rugged upland. 

The river valley in its course within the reservation nas an average 
width of 1 to 1^ miles. Farther up the river, between SolomonviUe 
and Fort Thomas, the valley is much wider, in some places reaching 
a width of 4 or 5 miles. The floor of the valley is formed of sediment 
deposited by the river in the trough channeled out of the lake beds. 

The river valley may be divided into river channel, flood plain, and 
terraces. The valley contains a series of low terraces at successive 
levels, each bordered by a steep bank. (See section C-C, PI. II.) 
These terraces have been formed by the continued lateral cutting 
and shifting of the river, together with slight downward cutting. 
The lowest flats, which are only 2 to 4 feet above the stream channel, 
are flooded during high stages of the river and therefore may properly 
be called the flood plain. 

SAN CARLOS BASIN. 

The San Carlos Basin, though not so well defined as the Gila Basin 
and of more irregular outline, has the same general types of 
topography. 

The valley of the San Carlos, like that of the Gila, has been chan- 
neled out of the older sediments that filled the rock basm and is bor- 



6 CONTRIBUTIONS TO HYDROLOGY OF UNITED STATES, 1919. 

dered by steep bluffs leading up to the dissected upland slopes that 
are underlain by these older sediments. The average width of the 
valley is from one-half to three-fourths of a mile. The valley floor, 
built up of recent sediments deposited by the river, has been terraced 
like that of the Gila. 

San Carlos River is an intermittent stream which rises in several 
branches in the western part of the Ash Flat plateau and flows in a 
general westerly direction to Rice, where it turns due southward and 
flows in that direction for a distance of 12 miles to its junction with 
the Gila at San Carlos. Two large draws empty into it in the vicinity 
of Rice — Gilson Wash, which extends along the railroad from Globe 
and joins the San Carlos at Rice station, and MacMillan Wash, which 
comes in from the north and joins the San Carlos 1 J miles above Rice. 

GEOLOGY. 

IGNEOUS BOCKS. 

The igneous rocks are represented chiefly in the mountain areas and 
in intervening parts of the plateau area north of the Gila Range, 
where large quantities of basalt have been poured out. Ash Flat, 
which lies between the Gila Range and the range to the north that 
forms the divide between the Gila and Salt river drainage basins, 
is largely floored by basalt, apparently of recent age. To the south, 
east, and north of the Triplets basalt has been poured out over the 
Quaternary basin deposits. Tuffs and breccias, products of this 
same period of volcanic disturbance, are interbedded with the basalts. 
East of San Carlos River remnants of basalt occur at a number of 
places overlying the soft Quaternary deposits. These lava caps, 
which have served to protect the underlying sediments against 
erosion, have produced flat-topped mesas which stand above the 
unprotected, irregularly eroded surface surrounding them. The 
most conspicuous example is. the Flatiron Mesa, 4 miles northwest of 
San Carlos. 

SEDrMENTABY BOCKS. 

PRE-QUATERNARY ROCKS. 

The rock complex that forms the core of the mountain ranges 
along the margins of these basins comprises not only igneous rock 
but various kinds of hard sedimentary rocks. The mountain areas 
in which these sedimentary rocks occur were not examined, but, to 
judge from the character of the debris that the streams have brought 
down from the mountains into the valleys, limestones are relatively 
abundant, especially in the Gila Range. Sandstones and various 
metamorphic rocks were also noted. 



SAW OABLOS INDIAN RESERVATION, ARIZ. 7 

QUATERNARY DEPOSITS. 
GENERAL CHARACTER. 

The oldest sediments in the Gihi and San Carlos basins consist of 
sand, gravel, and coarser rock debris laid down by streams and 
derived from the pre-Quaternary rocks that form the floors of the 
basins and constitute the mountains along their margins. These 
deposits were first studied by G. K. Gilbert in 1873 and named by 
him the Gila conglomerate.* 

On the eroded surface of the Gila conglomerate rests a series of 
well-stratified fine-grained soft sandstones, tuffs, marly clays, and 
limestones that were apparently deposited m a body of standing 
water and will in this report be referred to collectively as the lake 
beds. 

The youngest sedimentary deposits in the area consist of the allu- 
vium of the river valleys, which rests on the eroded surface of the 
lake beds. The river channels, flood plains, and terraces of the Gila 
and San Carlos river valleys are underlain by this material. 

GILA CONGLOMERATE. 

In general character and method of deposition the Gila conglomer- 
ate is comparable to deposits commonly laid down by streams in the 
closed desert basins of the Southwest, Along the upper Gila, where 
Gilbert first examined it, he noted its continuity with the fill of the 
valleys that open into the Gila. 

The Gila conglomerate in the San Carlos Indian Reservation 
consists of material ranging in coarseness from fine sand to boulders 
several feet in diameter. The materials are not firmly cemented but 
are coherent enough to form almost perpendicular cliffs in some 
localities. The conglomerate varies from place to place, both in 
the character of the constituent materials and in their arrangement, 
these features depending on the character of the rock from which the 
materials were derived and on the distance they have been trans- 
ported. On the higher slopes along the flanks of the ranges the 
conglomerate is generally composed of angular material of various 
shapes and sizes jumbled together in a confused mass without definite 
stratification. Near the axes of the basins, farther from the moun- 
tains, the materials are waterworn, sorted, and distinctly stratified. 
As is to be expected in deposits of this type, however, cross-bedding 
is common, and the individual beds lack persistency and grade from 
sand into gravel within short distances. 

The Gila conglomerate crops out in a belt skirting the southern 
flanks of the Gila Range, in a similar belt adjacent to the northern 

I Gilbert, G. K., U. S. Geog. and Geol. Surveys W. 100th Mer. Rept., vol. 3, pp. 540-541, 1875. 
124826°— 19— wsp 450a 2 



8 CONTEIBUTIONS TO HYDKOLOGY OF UNITED STATES, 1919, 

edge of the Tumbiill Range, and along the east side of the Pinal 
Range. (See PI. II.) It is carved into a great number of rounded 
ridges that are separated from one aiiother by deep gorges, forming 
a foothill belt that contrasts sharply* with the rugged ranges above 
and also with the intricately dissected but generally even surface of 
the long, sweeping slopes that extend from the lower limit of the foot- 
hills to the edges of the river valleys. 

The conglomerate belt that skirts the Gila Range on the north side 
of the basin extends across the east boundary of the' reservation. 
Withm the reservation it has an average width of about 3 miles and 
stretches from the east boundary northward about 15 miles and dis- 
appears beneath the lava flows centering about the Triplets. 

The conglomerate belt adjacent to the TurnbuU Range is 2 to 3 
miles wide and extends westward from a locality 4 miles southwest 
of the box canyon to a point south of Bylas. Beyond this point it 
was not traced, but it was seen to narrow considerably and to sweep 
southward along the eastern flanks of Moiuit Tumbull. At the upper 
margin it laps up against the range at an average altitude of about 
4,200 feet. Its general smface slopes at the rate of about 450 feet 
to the mile, and its lower limit corresponds approximately to the 
3,300-foot contour. 

The conglomerate area on the west side of the San Carlos Basin 
extends northward from the box canyon along the flanks of the 
eastern ridges of the Pinal Mountains. From the box^^canyon the 
conglomerate is easUy traced northward for 5 miles by its character- 
istic topography. Farther north the topographic distiifction becomes 
less marked, and the contact between the conglomerate and the over- 
lapping sandstone is not easily traced. 

As no complete sections were exposed the thickness of -the forma- 
tion could not be determined, but on the basis of the position and 
slope of the rock floor as determined in some of the canyons, and of 
the position and slope of the original upper surface of the formation 
as determined by the ridges of conglomerate, the maximum thickness 
of the Gila conglomerate in the middle of the Gila Basin is estimated 
to be not less than 1,000 feet. (See sections, PI. II.) 

■LAKE BEDS. 

Upon the eroded surface of the Gila conglomerate was deposited a 
series of sandstones, tuffs, limestones, and marly clays which wiU be 
referred to collectively as the lake beds, for they were evidently 
deposited in a body of standing water. This formation underlies 
the central and intermediate parts of the Gila and San Carlos basins, 
where it is at the surface except in the river valleys. (See PI. II.) 

The sandstone member of this formation is a soft, fine-grained, 
well-stratified buff sandstone, interbedded with thin layers or part- 
ings of a hard indurated sandstone of similar composition but usually 



lTER-SUPPLT paper 460 PLATE II 




y 



SYMBOLS IN SECTIONS 
a Alluvium 
b Lake beds 
c Gila conj/omerate 
d Basalt 



Undifferentiated pre-Quaternary 
seo/imentary, igneous^'antj metarriorphtc 
rodts not separated /n sect/ons 




Gila Peak 



EXPLANATION 



Alluvium 

(Sands and gravels 

in river valleys) 



Basalt 

(Intrusive masses and 
surface flows inter- 
calated m lake beds) 



X 






Lake beds 

(Well-bedded sandstona, 
marly clay, limestone, 
and tuff) 






Gila conglomerate 
(FluviatiU deposits of 
irregularly bedded 
semi consolidated 
sand, gravel, and 
coarse rock debris) 



BOOO'-i 



- c 



60O0'~ 
2000'- 



3 10 MILES 



Undifferentiated 
(Hard sedimentary, igneous, 
and metamorphic rocks, 
not separated on map) 



t maps. 



V. S. OKOIOOICAL SURVEY 



WATER-SUPPLY PAPER 450 PLATE II 




EXPLANATION 



Alluvium 
iSands and graveU 
in river vaileys) 



Baaalt 

(Inirusive vuusrs and 
siirfoee JUms inter- 
calated in lake betU) 



y//////A 



Lake beds 
(Well-bedded sandstone 
marly clay, limestone, 
and tuff) 



'/////'%/>/'y:M 






Gila conglomerate 
(Flumatile deposits of 
irre^idarhj bedded 
semi consolidated 
sand, gravel, arid 
coarse rock debris^ 



Undifferentiated 
(Hard sedimentary, igneous, 
and metamarpnic rocks, 
not separated (m map) 



GEOLOGIC MAP OF GILA BASIN AND PARTS OF SAN CARLOS BASIN. SAN CARLOS INDIAN RESERVATION, ARIZ. 
Base from plane-table maps by A. T. Schwennesen, U. S. Geological Survey topographic map of Chriatmaa quadrangle, and railroad alinement maps. 



SAN CARLOS INDIAN RESERVATION, ARIZ, 9 

of a somewhat coarser texture. Good sections are exposed in the 
bluffs that border the valley of Gila River and in the numerous 
canyons that open into the valley. 

The other members of the formation consist of interbedded light- 
colored tuffs, buff marly clays, and light-gray limestones, all of which 
are fomid principally in the region extending from the Triplets north- 
ward to San Carlos River and southward to the Gila. These rocks 
are prominently displayed in the bluffs on the east side of the San 
Carlos Valley between San Carlos and Rice and on both sides of the 
valley above Rice. 

The maximum thickness of the lake beds within the reservation is 
not known, as no complete sections are exposed. In the construction 
of the geologic sections (PI. II) an estimate of the thickness of these 
beds was made which is behoved to be reasonable. A surface passing 
through the crests of the ridges formed by the Gila conglomerate was 
assumed to represent the original surface of the Gila conglomerate. 
By projecting this surface beneath the lake beds and allowing for a 
gradual decrease in slope toward the axis of the basin the writer 
determined the approximate position of the surface upon which the 
lake beds would have been deposited if there had been no previous 
erosion of the conglomerate. In section D-D', Plate II, for instance, 
the general slope of the surface of the Gila conglomerate where it 
crops out on the south side of the basin is shown as between 4^° and 
5°, or about 450 feet to the mile. This surface projected beneath the 
lake beds, with allowances for decrease of slope northward, gives an 
elevation of approximately 2,000 feet above sea level at the axis of 
the basin, or about 600 feet below the surface of the river valley. 
Similarly, section C-C, which crosses the valley of Gila River be- 
tween Calva and Dewey Flat, shows the bottom of the lake beds to 
be about 600 feet below the surface at the axis of the basin. The 
lake beds at San Carlos (section B-B') are estimated to be about 800 
feet thick, and those at Peridot (section A-A'), in the valley of San 
Carlos River, about 700 feet. If the conglomerate was deeply dis- 
sected before deposition began the maximum thickness of the lake 
beds may be greater. 

The lake beds generally have a slight dip toward the river valleys. 
On the south side of the Gila the dip is from 1^° to 2'' N. West of 
San Carlos River the beds have a slight dip toward the east. North 
of the Gila and east of the San Carlos they appear to be nearly 
horizontal. 

The formation seems to have undergone little folding or faulting. 
SUght folding and minor faulting were noted in the hmestone beds 
exposed m the bluffs of Gila River just east of its junction with the 
San Carlos. An east-west fault was also noted in the vicinity of a 
lava flow 2 miles west of Flatiron Mesa, on the west side of the San 



10 CONTRIBUTIONS TO HYDROLOGY OF UNITED STATES, 1919. 

Carlos Basin. Faulting has probably occurred in connection with the 
disturbances that accompanied the outpouring of the lava at other 
places. 

ALLXTVIUM. 

The youngest sedimentary deposit in the area is the alluvium of 
the Gila and San Carlos valleys. It consists of sand and gravel laid 
down in troughs channeled out of the lake beds. Most of the fine 
material has been deposited by the rivers and resembles the material 
that forms the bottoms of the present channels. The gravel has for 
the most part been brought down through the arroyos opening into 
the valleys from the sides. 

QtrATERNABY HISTORY. 

The Quaternary history of the region can be outlined as follows : 

1. Aggradation in the rock troughs, resulting in the deposition of 
about 1,000 feet of gravelly alluvium and the construction of large, 
steep alluvial slopes. 

2. Erosion of the alluvial slopes. 

3. Submergence of the lower parts of the alluvial slopes by a lake. 
Deposition of sand, tuff, and other sediments in the lake to a maximum 
depth of probably 800 feet. Continued erosion of the parts of the 
slopes that were not submerged. 

Volcanism, resulting in the outpouring of basalt, the deposition of 
tuff, and minor faulting and folding, at least chiefly, in the later part 
of the period covered by epochs Nos. 1, 2, and 3, but may not have 
been confined to No. 3. 

4. Disappearance of the lake. The cause of the formation of this 
lake and that of its disappearance are not known. Excavation of 
the valleys by Gila and San Carlos rivers in the old lake bottom, and 
intricate dissection of the lake bottom near the river valleys. 

5. Partial refilling of the river valleys through deposition by the 
streams, followed by slight changes in stream grade that resulted in 
the formation of a series of low terraces. Continued erosion of the 
lake bottom. 

Erosion of the older alluvial slopes was practically continuous after 
epoch No. 1 ; the erosion of the mountain ranges continued through- 
out the period, and the erosion of the lava beds began immediately 
after their extrusion and continued without interruption. 

CLASSIFICATION OF LANDS. 

The lands of the Gila and San Carlos valleys may be classed as 
arable or nonarable on the basis of their suitability for farming and 
irrigation if a water supply is provided. Their suitability for this 
purpose depends in part on their topography and the quality of their 
soil. 



V. S. GE01X)GICAL SURVEY 



WATER-SUPPLY PAPER 450 PUTE 








ARABLE LAND 

Low terraces whkh indude the 

diboM fBVoraUoforirTiB»lLon 
development. AcrMx« indi- 
cated ihiw:f3/J*^.)Tota]. *.m 







Scale -t^ToCb 


1 






ZM 


LES 


















EXPLANATION 








































® 




f 


l» 


pUin. «hM, 1 
iidjaccnlt^lh 


•f 


is 


^i 


^•SS»I 


^ "™ 


tr.h'n^,," 


respond to 
desigiute 


Appr 


erin 
respo 


l« locatio 


Mtrtln, 


Spring 



-^Q QQ3jrp|^TmTT'TnTgS-Ji;Q-ii3aMajax^c>^^ 



ARABLE LAND 

z 




'///////A 



V^erraces which includ 
s with soil and otheij 
ms favorable for irrigj 
;lopment. Acreage 
d thus: (75^.) Total, 




lative vegetati 



U. s. GEOLOGICAL SURVEY 



WATER-SUPPLY PAPER 450 PLATE W 



NONARABLE LAND 



EXPLANATION 
ARABLE LAND NONARABLE LAND 




22 „5 



Flood plains which include low Low terraces which include the Terraces and uplands with dis- Wells Numbers correspond to 

lands adjacent to the river and lands with soil and other con- sected surface and rocky soil. numbers used to designate 

which are nonarable on account ditions favorable for irrigation Land not suitable for farming wells in the text 

of yearly overflow development. Acreage indi- 



Jfi&. 




■ ••^-ijy 



S 5 E C T E n ~ I'l^""^?^ 
UPLAND 



UPLAND 



-.Mesquite' 



^//Z' . ■■//{•■'- '■■■ ^{'Ifchiionvyoo'c^s 



i$oiidnwbd'd^^y^^,.4; ■/■.-Uj P''/l': '.and brush 



5IDING ''\ii/ ,^v'■■""V' ,1, .,1 




U P L " A N D 



,:^5:^ 



Sase compiled from plant^'table map byA.TSchwenm 



MAP OF A PART OF SAN CARLOS VALLEY, ARIZONA, ABOVE PROPOSED SAN CARLOS RESERVOIR SITE 

Showing classification of lands and location of wells, with some notes on the predominant native vegetation 

and the condition of the soil and surface 



~l 



SAN CARLOS INDIAN RESERVATION, ARIZ. 11 

All the lands that lie at a sufficient elevation above the rivers to 
be out of reach of floods, whose soil is satisfactory, and whose surface 
can be prepared for cultivation and the application of irrigating 
water with a reasonable amount of labor and expense have been 
classified as arable lands. These lands are for the most part on the 
low terraces. The soils are light and well drained. Among the 
native plants growing on the uncleared tracts mesquite and cat-claw 
predominate, but cottonwood trees are also common. 

In the valley of Gila River above the proposed San Carlos reservoir 
site there is, as nearly as could be determined, 4,595 acres of land 
which may be classed as arable. This area includes 421 acres irri- 
gated and farmed in the Bylas district in 1913. (See PI. III.) 

In the main valley of San Carlos River above the proposed reservoir 
site the amount of arable land, including that irrigated under the 
present system, is approximately 1,840 acres. (See PL IV.) 

The nonarable lands consist of the river channels, the flood plains, 
or river bottoms, and the terrace lands near the edges of the vaUey 
where the surface is too uneven or the soil is too gravelly for farming. 
Cottonwoods, wiUows, and certain unidentified water-loving shrubs 
grow as thickets on the flood plains. The higher gravelly tracts near 
the bluffs are the favorite habitat of the creosote brush and members 
of the cactus family. 

Along Gilson Wash, which enters the vaUey of San Carlos River at 
Rice, and MacMillan Wash, which enters it IJ miles above Rice, are 
numerous small tracts of land that could probably be successfully 
farmed if water were available, but these lands have not been included 
with the area classed as arable. 

SURFACE WATER SUPPLY. 

The only streams in the area under discussion that offer a possible 
source of water supply in sufficient quantities for irrigation are Gila 
River and San Carlos River. Both streams head in areas where 
melting snow furnishes considerable flow during the early spring 
months, but about the last of April the snow disappears and the 
streams fall rapidly, reaching a minimum about the first of July, when 
the summer rains ordinarily begm. The most severe droughts, 
however, occur during July and August in years when the summer 
rains fail or are not of sufficient intensity to swell the streams. 

The total annual run-off of Gila River, even during the lowest years, 
is undoubtedly more than sufficient to irrigate aU the arable land 
in the reservation, but without storage it is of little value, because it 
passes during the months when it is least needed or in floods so intense 
that it can not be conducted to the land without unduly expensive 
diversion dams. 



12 CONTRIBUTIONS TO HYDROLOGY OF UNITED STATES, 1919. 

San Carlos River is ordinarily dry for a considerable part of eacli 
year, but if the total run-ofT during normal years could be economically 
stored it would probably be sufficient to irrigate several thousand 
acres of land. It is doubtful, however, if feasible storage sites exist 
on this stream. 

The following tables give the essential results of measurements of 
stream flow on Gila River in the vicinity of San Carlos and on San 
Carlos River that have been made by the United States Geological 
Survey. The records of flow on GUa River at San Carlos from 1899 
to 1905 are of exceptional value and interest, in that they cover a 
period of the most severe drought that has been experienced in the 
history of modern agricultural development in Arizona. 

GILA RIVER AT SAN CARLOS, ARIZ. 

Location. — Half a mile south of San Carlos Indian Agency at San Carlos, Gila County, 
half a mile below San Carlos River, and about 7 miles above dam site in box 
canyon. 

Records available. — ^July 11, 1899, to November 27, 1905 (incomplete). From 
August 17, 1910, to February 5, 1911, a station was maintained just below the 
Arizona Eastern Railroad bridge and half a mile above San Carlos River. Because 
of insufficient data discharges have not been computed for this station. For 
discharge measurements and gage heights see Water-Supply Papers 289 and 309. 

Gage. — Inclined staff on right bank. 

Discharge measurements. — Made from cable a short distance above gage. 

Channel and control. — Sandy and badly shifting. 

Extremes of discharge. — Discharge varies from zero flow to enormous floods, 
probably exceeding 100,000 second-feet. No accurate measurements of extreme 
floods have been made. 

Diversions. — Water for irrigating several thousand acres was diverted above the 
station for use in the Solomonville and Duncan valleys. A small amount of 
water (probably not exceeding 5 second-feet at any time) was also diverted just 
above the gage for irrigating lands within the reservation. 

Accuracy. — Results liable to considerable error, particularly during low stages, on 
account of shifting channel and c'ontrol. 



SAF CARLOS INDIAN RESERVATION, ARIZ. 



13 



Monthly discharge of Gila River at San Carlos, Ariz., for 1899-1905. 



Month. 



Discharge in second-feet. 



Maximum. Minimum. Mean 



Run-ofF in 
acre-feet. 



July 11-31.... 

.'Vujiu.st 

September . .. 
Octoberl-18. 



The period. 



April 4-30 . 

May 

June 

July 

August 

September. 

October 

November. 
December. . 



1900. 



The period. 



January 

February . . 
March . .". . . 

April 

May 

June 

July 

August 

September. 

October 

November. 
December. . 



1901. 



The vear. 



January 

February . . 

March 

April 

May 

June 

July 

August 

September. 

October 

November. 
December. . 



1902. 



The year. 



January 

February . . 

March 

April 

May 

June 

July 

August 

September. 

October 

November. 
December. . 



The year. 



11,000 

2,740 

6,860 

300 



2.750 
6,900 

102 
2,900 

118 



1, 150 

2,110 

1,080 

155 

8 

6 

3,600 

1,870 

1,700 

460 

630 

155 



3,600 



94 

57 

26 

2 





400 

1,820 

340 

4 

30 

2,750 



2,750 



360 

73 

110 

147 

8 

670 

575 

,570 

.150 

405 

78 

43 



195 
90 



1,760 
408 
416 
143 



3.5 
.9 
.3 
.1 
1.0 
25 
36 
10 
66 



5.7 
2.4 
.6 
.3 
198 
937 
60.0 
177 
102 



36 

420 

155 

6 

4 

o' 

67 
18 
10 
133 
94 



141 
1,110 
426 
59.3 
5.5 
2.6 
377 
482 
212 
67.5 
223 
110 



262 



79.1 
45.9 
13.5 
.1 
.0 
.0 
28.2 
407 
114 
.1 
1.2 
583 



107 



1 
16 
38 
42 
22 



169 
.'■)3.3 
35.7 
50.6 
2.2 

107 
53.3 

963 

223 

106 
55.4 
35.5 

156 



73,300 

25, 100 

24,800 

5,110 



128,000 



305 

148 

36 

18 

12, 200 

,55,800 

3,690 

10,500 

6,270 



89, 000 



8,670 
61,600 
26,200 

3,530 
338 
155 
23,200 
29,600 
12,600 

4,150 
13, 300 

6, 760 



190,000 



4,860 

2.550 

830 

4 





1.730 

25,000 

6.780 

8 

71 

35,800 



77,600 



10, 400 
2,960 
2,200 
3.010 
135 
6,370 
3,280 
59,200 
13,300 
6,520 
3,300 
2,180 

113,000 



14 CONTRIBUTIONS TO HYDROLOGY OF UNITED STATES, 1919. 

Monthly discharge of Gila River at San Carlos, Ariz., for 1899-1905 — Continued. 



Month. 



Discharge in secx)nd-feet. 



Maximum. Minimum. Mean, 



Run-oflin 
acre-feet. 



1904. 

January 

February 

March 

April 

May 

June 

July 

August 

September 

October 

November 

December , 

The year 

1905. 

January 1-11 

May 14-31 

June 

July 

August 

September 

October 

November 1-27 



36 

48 

15 

12 

115 



1,580 

3,200 

1,300 

5,870 

210 

660 



27 

17 

9 

2 







240 

20 

20 

42 

31 



31.7 
32.6 
11.0 
5.3 
8.7 

143 
952 
232 
825 
112 
306 



5,870 



7,000 

1,400 

675 

740 

1,090 

1,650 

705 

6,150 



224 



120 
440 
30 
5 
110 
68 
28 
58 



1,290 

949 

255 
99.6 

441 

544 

149 
1,100 



1,950 

1,880 

676 

315 

535 



8.790 

58,500 

13,800 

50,700 

6,660 

18,800 



163,000 



28,100 
33,900 
15,200 

6,120 
27,100 
32,400 

9,160 
58,900 



Note.— No record for the periods Oct. 19, 1899, to Apr. 3, 1900, and Jan. 12 to May 13, 1905. 
GILA RIVER NEAR SAN CARLOS, ARIZ. 



Location. — One mile above dam site in box canyon, in San Carlos Indian Reserva- 
tion, about 6 miles below San Carlos Indian Agency, Gila County. 

Records available. — April 29, 1914, to September 30, 1917. 

Gage. — Stevens water-stage recorder on left bank about 1 mile above dam site. 

Discharge measurements. — Made by wading near gage or from cable about 1 mile 
above gage. 

Channel and control. — Channel composed of sand, gravel, and boulders. A semi- 
permanent control is formed by rapids over heavy boulders just below gage. 
Control shifts somewhat because of sand filling in and washing out from crevices 
between the boulders. 

Extremes of discharge. — 1914-1917: Maximum stage 25.5 feet January 20, 1916 
(approximate discharge, determined from extension of rating curve, 92,000 sec- 
ond-feet); minimum stage 0.15 foot, July 1, 1914 (discharge, 1 second-foot). 

Diversions.— Water for irrigating about 30,000 acres is diverted from river in valley 
just above station. At times this diversion reduces the low flow practically to 
zero at the station. About 7,000 acres is irrigated from this stream above the 
station at Guthrie. 

Accuracy. — Results fair except for extremely high or low stages or for estimated 
periods. (See footnote to monthly discharge table.) 



SAN CARLOS INDIAN RESERVATION, ARIZ. 



15 



Monthly discharge of Gila River near San Carlos, Ariz., for years ending Sept. 30, 1914- 

1917. 



Month. 


Discharge in second-feet. 


Run-off (in 


Maximum. 


Minimum. 


Mean. 


acre-feet). 


Mav 






8 

725 

968 

1,080 

612 


492 


Juno 


405 
2,380 
3, 220 
2, 430 


3 

1 

291 

120 


4,310 


Jul V 


69,500 


August 


66,400 


September 


36, 400 






The period 








167,000 












1915. 
October 


6,150 
3,220 


116 
250 
490 


1,170 

781 

6,180 

2,420 

3,950 

3, 570 

3,870 

1,130 

193 

907 

500 

207 


71,900 


November 


46, 500 




380,000 


January . - - 




149,000 








219,000 


March ^ 






220, 000 


April 






230,000 


Mav 






69,500 


June 






11,500 


July 






55, 800 


August 






30, 700 


September 






15, 900 










The year 






2,100 


1, 500, 000 










1916. 
October 


164 
134 
387 


26 
26 
130 

387 


66.7 
71.5 
222 
12,800 
3,290 
2,890 
1,080 
403 
57.3 
87.6 
788 
720 


4,100 


November 


4,250 


December 


13, ()00 


January 


787,000 


February 




189,000 


March 






178,000 


AprU 


2,410 

968 

121 

190 

1,770 

2,670 


533 

127 
17 
12 

144 

128 


64.300 




24,800 
3,410 


June 


July 


5,390 


August 


48, .500 


September 


42,800 






The year 




12 


1,890 


1, 370, 000 








1917. 
October 


33, 500 

822 

444 

14, 400 

1,550 

1,910 

938 


103 

330 

316 

328 

514 

418 

190 

72 

15 

14 

57 


3,240 

442 

347 
1,850 

964 

774 

482 

152 
34.8 

187 

221 
48.2 


199,000 


November 


26,300 


December 


21,300 


January 


114,000 


February 


53,500 


March 


47,600 


April 


28,700 


May 


9,350 


June 


66 
1,050 

827 


2,070 


July 


11,500 


August 


13,600 


September 


2,870 










The year 


33,500 


14 


732 


530, 000 







Note. — Mean discharge for May and December, 1914; January to September, and December, 1915; Jan- 
uary to March, and December, 1916; and May and September, 1917 estimated or partly estimated by com- 
parison with records at other stations on this stream. 



SAN CARLOS RIVER AT SAN CARLOS, ARIZ. 

Location. — Opposite railroad station at San Carlos, Graham County, in San Carlos 
Indian Reservation, about half a mile above junction with Gila River. 

Drainage area. — Not measured. 

Records available. — August 17, 1910, to January 12, 1911, ^ and April 1, 1914, to 
September 30, 1915, when station was discontinued. 

1 Discharge not computed from Aug. 17, 1910, to Jan. 12, 1911. For discharge measurements and gage 
heights see Water-Supply Papers 289 and 309. 



16 CONTRIBUTIONS TO HYDR'^LOGY OF UNITED STATES, 1919. 

Gage. — Stevens "water-stage recorder on left bank. The original gage, which was 
used from August 17, 1910, to January 12, 1911, was a vertical staff fastened to 
right pier of railroad bridge, downstream end. 

Discharge measurements.- — Made by wading or from cable at gage. 

Channel and control.— Sand, badly shifting at all stages. Section flat and non- 
sensitive. 

Extremes of discharge.— Stream dry a part of each year. July 26, 1915, a heavy 
flood occurred, covering the surrounding lowlands. Discharge not determined. 

Diversions. — No record of any diversions, although a small amount was probably 
diverted above the gage for irrigation. 

Accuracy. — Results poor because of shifting control and insufficient discharge meas- 
urements. 

Monthly discharge of San Carlos River at San Carlos, Ariz., from Apr. 1, 1914, to Sept. 30, 

1915. 



Month. 



Discharge in second-feet. 



Maximum. Minimum. Mean 



Run-off in 
acre-feet. 



April 

May 

June 

July 

August 

September 

October 

November 

Decembel-1-18. 







21 

165 

145 

90 

375 

290 

150 







2.1 

12.8 

47 

32.3 

59 

60 

63 







125 

762 

2,800 

1,920 

3,630 

3,570 

2,250 



The period. 



292 



January 1-28.- 
February 1-19. 

March 

April 

May 

June 

July 1-25 

August 

September 



1915. 



145 
210 
160 
190 
132 
155 




79 

128 

97 

46 

36 

2.6 



ol5 

05 



15, 100 



4,390 
4,820 
5,960 
2,740 
2,210 

155 


920. 

300 



o Estimated. 

Note. — Floods above the limit covered by the rating curve occurred during the period Dec. 19-30, 1914, 
Jan. 29-31, Feb. 20-22, and July 26-31, 1915. Discharge Dec. 31, 1914, 150 second-feet. Mean discharge 
Feb. 23-28, 1915, 15.7 second-feet. 

PRESENT IRRIGATION. 



All irrigation on the reservation in 1914 was done with water from 
the Gila and San Carlos rivers, diverted into the main canals by 
brush and earth dams thrown across the channels. These dams are 
temporary affairs that wash out at each flood and must be rebuilt at 
the beginning of each irrigating season and perhaps several times 
during the season. They are necessarily low and are too frail to 
impound the water and raise it much above its natural level, so that 
the intake of the ditch can be little higher than the bottom of the 
channel. This condition allows little opportunity for the silt to 
settle before the water is taken into the canals. Consequently the 
canals, especially those on the Gila, become choked with silt and must 



SAN CARLOS INDIAN RESERVATION, ARIZ. l7 

frequently be dug out. Flood waters discharging into the canals 
through gullies from the sides of the valley also deposit much silt and 
often destroy sections of the canjils by cutting across them. 

Permanent dams that could withstand the floods would save much 
expense and also relieve the present water shortage to some extent, 
for much water is now lost by seepage through the temporary dams, 
even when the rivers are low. On account of the unstable character 
of the bottom and sides of the channels, however, permanent dams 
may not be practicable on Gila River. On the upper San Carlos a 
suitable site for a permanent dam could probably be found, but 
whether the additional land that could be irrigated with the water 
saved by a permanent dam would warrant its construction is not 
certain. 

The enlargement of the present irrigation system on Gila River to 
include more of the arable lands in the valley would require the con- 
struction of canals at higher levels than those now in use. If per- 
manent dams are not practicable the construction of high-level canals 
would necessitate either carrying the ditch head much farther up the 
river and outside of the reservation, or else pumping from the river 
into the high-level canals. 

The most serious drawback to the present irrigation system is the 
inadequacy of the water supply during certain months of the year. 
Gila and San Carlos rivers are usually lowest in May, June, and July, 
the months during which water is most needed. It is not unusual for 
these streams to dry up entirely at times. during these months, so that 
it becomes necessary to scrape out holes in the sand and gravel of the 
channels to provide water for stock. According to the stream-gaging 
records of the United States Geological Survey for 1914 no water 
passed the gaging station on San Carlos River at San Carlos during 
April and May, but in June 125 acre-feet and in July 762 acre-feet 
passed the station. At the gaging station above the box canyon on 
the Gila the average flow for the first 22 days after the automatic gage 
was in operation, from May 27 to June 17, was 18 acre-feet per day. 
As these records were obtained below the irrigated districts of the 
reservation they do not show the amount of water taken out by 
ditches. 

The yearly cost of keeping up the ditches and diversion dams on the 
reservation is from $1,800 to $2,000. In 1913 the expenditure in 
preparation for the season's irrigation was $1,908, according to the 
statement of the superintendent, A. L. Lawshe. The total area 
irrigated, according to Mr. Lawshe, was 1,428 acres, of which 421 
acres was in the Bylas district, 469 acres in the San Carlos district, 
and 538 acres in the Peridot district. The cost per acre was there- 
fore $1.34. 



18 CONTRIBUTIONS TO HYDROLOGY OF UNITED STATES, 1919. 

SHALLOW GROUND WATER. 

OCCURRENCE AND QUANTITY. 

Water is found at shallow depths in the Recent alluvial fill of the 
Gila and San Carlos valleys. Most of the wells are on the low terraces 
above the stream channels. Most wells dug by the Indians for 
domestic water supplies are not more than 15 or 20 feet deep, but 
several constructed by white settlers on higher ground are deeper. 
The Rice school well, at the base of the bluffs on the north side of 
San Carlos Valley (No. 3, PL IV), is 36 feet deep and has a depth to 
water of 32 feet. Two large dug wells at the flour mill at San Carlos 
are 30 and 32 feet deep. The weU at the railroad station at Calva, 
near the foot of the bluffs on the south side of Gila Valley (No. 13, 
PL III), is 75 feet deep, and the water table here is 45 feet below the 
surface. 

The shallow wells on the level arable terraces end in sand and fine 
gravel similar to the material in the present stream channels. The 
general correspondence of the water level in the wells with the level 
of the water in the streams indicates that the alluvium is saturated 
about to the stream level. 

The water is supplied by percolation from the rivers, by water dis- 
charged into the valleys through tributary arroyos, and by direct 
rainfall on the valleys. The principal contributions are probably 
made by percolation of stream water into the bottoms and sides of 
the river channels. Second in importance are contributions made by 
tributary arroyos, a part of whose water sinks into the gravel near the 
edges of the valleys. The amount of water contributed by direct 
rainfall is relatively small. The rapidity with which water with- 
drawn from wells is replenished depends on the porosity and continuity 
of the water-bearing beds and the location of the wells with respect 
to the streams. Wells close to the stream channels will probably 
yield more freely than wells farther back, at a greater distance from 
the principal source of supply. Where large quantities of water are 
required it is therefore generally not advisable to sink wells at very 
great distances from the streams. 

The lake beds, which underlie the Recent alluvium, yield some water 
but do not constitute good water-bearing material. The large dug 
weUs at the San Carlos flour miU, on the gently sloping ground above 
the San Carlos bottoms, penetrate about 15 feet of coarse sand and 
gravel and then pass into the lake beds. The upper sands and 
gravels are above the water level and are therefore dry, and the 
water is said to come out of thin "clay" seams in soft fine-grained 
sandstone. The weUs are about 30 feet deep and have an aggregate 
cross-sectional area of about 1,400 square feet. In summer about 
50,000 gallons of water is pumped from them during a 10-hour day. 



SAN CARLOS INDIAN RESERVATION, ARIZ. 19 

At this rate these large wells are soon pumped down, and in order to 
continue pumping it is necessary to put into operation a syphon 
comiectmg the large wells with a well on the terrace of San Carlos 
River. When pumping is continuous this well, which is only 10 feet 
deep and 8 by 8 feet in cross section and which ends in Recent allu- 
vium, furnishes most of the water. 

A number of years ago two wells were drilled from the bottom of 
the larger of the two wells at the flour mill in the hope of getting an 
increased supply from a deeper stratum. One of these wells reached 
a depth of about 115 feet, and the other was sunk to a depth of 385 
feet below the surface. Both wells were failures, although in the 
3S5-foot well a small supply of water was obtained at 85 feet. All the 
way down these wells were in the same fine-grained sandstone — 
probably belonging to the lake beds — found in the lower parts of the 

dug wells. 

QUALITY. 

The mineral character of waters from wells and from Gila River 
is shown in Tables 1 and 2. The samples whose analyses are 
given in Table 1 were collected by the writer in the course of the field 
investigation. Table 2 gives the results of analyses of waters from a 
number of shallow test wells put down in the Gila Valley several years 
ago under the direction of James W. Martin, superintendent of irriga- 
tion for the Indian Office. 

In samples 1, 9, 12, 13, and 14 (Table 1), which represent waters 
from shallow wells in the Gila Valley above the proposed San Carlos 
reservoir site, the amount of total solids ranges from 1,330 to 2,412 
parts per million. Samples 9, 12, 13, and 14 are very high in their 
content of chlorine, one of the constituents of sodium chloride or 
common salt, ordinarily referred to as one of the "white alkalies." 
These waters are practically worthless for irrigation under ordinary 
conditions. Sample 1 contains less sodium chloride but contains a 
prohibitive amount of sodium carbonate or ''black alkali," which is 
even more harmful than white alkali. The sample of water from 
Gila River at the canal intake is representative of the water now used 
for UTigation on the reservation. Comparison with the well waters 
shows that it contains less than half as much white alkali. The fact 
that it has been used successfully for many years for the irrigation 
of crops in the Gila Valley is sufficient proof of its value as an irrigat- 
ing water. The effects of its continued use, however, are shown by 
the alkah spots that appear in the alfalfa fields, and it is questionable 
whether the crops could endure a much greater amount of these salts. 
A doubling of the amount of alkali, which would result from the use 
of well waters such as the analyses represent, would probably prove 
fatal to most crops, even under the most favorable conditions of soil 
and drainage. 



20 CONTRIBUTIONS TO HYDROLOGY OF UNITED STATES, 1919. 

The sample from the pmnping plant at San Carlos (Table 1) is a 
mixed water from wells at the flour mill and a well about 500 feet 
northeast of the flour mill, on the San Carlos River bottoms. This 
water contains less soluble salts than any of the other well waters 
that were analyzed. It contains a moderate arhount of white alkali 
and a small amount of the more injurious black alkali. As an irrigat- 
ing water it may be classed as fair, and in its probable effects on crops 
it is comparable to the water from Gila River. 

Unfortunately no analyses of well waters from the San Carlos 
Valley are available. A sample thought to be fairly representative 
of well waters in the San Carlos Valley was obtained from a driven 
well near the river at the new steel bridge across the San Carlos. 
The sample was too small for a complete analysis, however, and 
therefore no report on this water was obtained. 



SAN CARLOS INDIAN RESERVATION, ARIZ. 



21 



I o 



W3 a^ 



So coO 
<" el fe ta r"^ 



-go 



C3^' 



03 



Q Q Q 



1^ ■* O 05 

S? S 2 ?3 



S S 



S ?5 









So S 



»rt rt -< t- 



■go 



o « 



fja en 






>. .J, 

C— M 
f G> -. 

9 oO 



8 " 



.a«R°^S6o 






« R o 

o ■" s a'oQ t- b « 

'^a:i°„ao3tS 



;z;fe 



|I.T3 03 



fto£ 



^S-S 



t»0> 03 
(floS 



SoS 

• So 

CO R 

..•* 03 

I 11-2 

S 03 t- 

2^.23 
•5:2 CO 



■" g b CO 

» o 2 o 



o 3 S I 

>- c P.O 

c3 o'~'"T' 
'*'0 .00 
C o3c<5^ 

03 o'^O 

£2.2 + 






s 03 a 



JO 



^w-qM c3 CO 

«S^Sg o 

« " ocD a S 

to a ii '^ 9 a 

OJ R CO O OT 

"C ^'l^ j3 ® CO 

ov-'.a 03 3 a 

■^w_g43ft O 

<u o c3 CO g .-3 

3X!.i<( So g 

": 03 o— ' ., " 

w+^ 03 co-O !- 
R C CO 03 O) 

a; "^ WM t.K.2; 

CO OJ-o^ „ l^ S 



ilsa- 






22 CONTRIBUTIONS TO HYDROLOGY OF UNITED STATES, 1919. 



.a 



'^ 



^ 
s 



^ 



o 



S ^„ 



5-! 


o S 


(^ 


se 


S 




« 


'^ 




►^ 






rM"-* 






o 


■2 S 














O 




s 


a« 


w 


03 .tS 


cq 


o^ 






r« 






SS 


S' 


S fl 


•.s> 


«■& 






O 01 



§1 








d 


lack 

ex- 
uble 


03 ot3 






-" VT? 


— 'T3 




d 


o o 






.1 


B o o 

C3 


°1 ° • 




be 

'b 

o 


CO w TO ^ 




.i 


g §1 






s 


1 Is 






§ -K 


.-S^-Sg 




1 






Q 


S-^ CB S- 














^"Slffis 


w O 03 O M 






o o 


^ ;? 




S 


• bj 






1 




03 


: s 










f5 


o o 










O 


-M tH 










=3 "S 


W) o 




03 


1 ^ 


1 " 








: M 












: CI 










ffi 


Oi o 








■2 


B 


^ a 








'3 


3 




tug o 1 


a 




o S 


tH 




§ 




S > 


m 




« 










> 






































03 
















.s 


-i-a 










"3 








-2 




iS" 


C5 


•5 bf 






03 




o 






<1> 


: bi 












H 










03 


a> o 








ft 


g ^ 


2 5. 







"3 


■§ b 


-§ g 




CQ 


O OJ 


o t- 






S > 


1:^ 02 


CO 


1 q- - 


r- (N 


OS w 


03 
& 


^ ;i.g°o 


Ol CO 


CQ <N 








*w ^ 


^■"^^ 






^-a" 


m OT • 


co o 


o o 




ill 


CO 1-1 

o 




1^ 

ta ft 


g-g-s 
















Tji Ml 


Tt^ O 


1 


^s^ 


00 t- 


c» OD 


^°is 


^'' 


^" im" 


3, 


1— 1 




c? 


g^ 






• 




^ 1 








° S;'©^ 




o 


1 63 

" fl 03 


3 »S« 

gO"S 

•S w O m 

2-1 gs| 




CQ 












•a+^ ft 


IP II 






M° hop, 








sPh 3 O 






fl Pi 


ft ft 




io , «. 














3 a a 














ij a o 












f 


:,«-42 


< PC 




c 


C 





SAN CARLOS INDIAN RESERVATION, ARIZ. 23 

XJSE FOB IRRIGATION. 

Although no definite tests have been made there is reason to believe 
that the recent alluvium would yield enough water, if pumped from 
shallow wells, to u'rigato all the arable lands. As the principal 
contributions to the ground-water supply are received from seepage 
of the streams into the bottoms and sides of the stream channels, 
wells should be located as near the chamiels as possible if large yields 
ai'e desu-ed. Wells and pumping plants should, however, be placed 
where there is no danger that they wUl be washed out, for the streams 
are continually changing their courses and wearing away the lands 
adjacent to their channels. 

Irrigation with water pumped from wells would have an important 
advantage over irrigation with surface water in that the supply 
would be nearly uniform throughout the year, whereas surface sup- 
plies are most abundant when irrigation is not needed and least 
abundant in the dry season. Its cost would be considerably higher 
than the present cost of irrigating with surface water, but this higher 
cost would be compensated to a large extent by an increased crop 
yield made possible by an assured water supply in the dry season, 
during which the crops often suffer. 

The principal objection to the use of water from wells is the poor 
quality of the water. The waters of the Gila Valley are so heavily 
impregnated with mineral matter as to require extraordinary pre- 
cautions to prevent the accumulation of an injurious amomit of 
alkali in the soil, and it is doubtful whether they could be successfully 
used for any length of time even under the most favorable conditions 
of soil and drainage. The data as to the quality of the ground waters 
of the San Carlos Valley are meager, but there is reason to believe 
that these waters are better than those of the Gila Valley. 

Final judgment as to the availability of the shallow ground waters 
may well be deferred until practical tests have been made and their 
effects on crops noted under actual working conditions. Experiments 
of this kind should be carried on at the Bylas farm, in the Gila 
Valley, where a small pumping plant has lately been installed, and 
similar experiments should be made in the San Carlos Valley. 

To the extent that the shallow ground water is found to be good 
enough for irrigation, it can be used advantageously on the tracts 
now imder cultivation to supplement the inadequate sm-f ace water 
supply, and also on the arable tracts that lie above the present ditch 
system. 

ARTESIAN WATER. 

The principles upon which artesian flows from sedimentary rocks 
depend are explained in textbooks on geology and in many of the 
publications of the United States Geological Survey. The necessary 



24 CONTRIBUTIONS TO HYDROLOGY OF UNITED STATES, 1919. 

conditions are concisely stated by T. C. Chamberlin ^ as follows : 
(1) A pervious stratum to permit the entrance and the passage of 
the water; (2) a water-tight bed below to prevent the downward 
escape of the water; (3) a like impervious bed above to prevent 
escape upward, for the water, being under pressure from the fountain 
head, would otherwise find relief in that direction; (4) an inclination 
of these beds so that the edge at which the waters enter will be 
higher than the surface at the well; (5) a suitable exposure of the 
edge of the pervious stratum, so that it may take in a sufiicient 
supply of water; (6) rainfall adequate to furnish this supply; (7) 
absence of any means of escape for the water at a lower level than 
the surface at the well. 

In the Gila Basin and in the lower part of the San Carlos Basin 
the essential conditions for an artesian flow as stated above are be- 
lieved to be fulfilled, the Gila conglomerate serving as the pervious 
stratum for the entrance and passage of the water, the rock floor 
upon which it rests serving as the lower impervious stratum, and the 
lake beds serving as the upper impervious stratum. (See section D-D ^, 
PL II.) 

Wherever the Gila conglomerate is exposed it has the appearance 
of a good water-bearing material. Its outcrops along the flanks of 
the ranges, several hundred feet above the river valleys, provide a 
large intake area for the absorption of direct rainfall and run-off 
from the mountains above. If the conglomerate extends to the 
axes of the basins and is of the same character as at the outcrops, it 
fulfills the first requisite given above. Its character near the axes 
of the basins, where it is hidden beneath the overlying formations, 
can only be conjectured. It probably contains less coarse material 
there than where it crops out, but there is no reason to believe that 
it is entirely devoid of water-bearing gravels. 

The rock basins in which the Gila conglomerate lies appear to be 
sufficiently tight to prevent the escape of ground water. At their 
lower ends the Gila and San Carlos basins are closed by mountains 
that allow the escape of surface water through a narrow gorge (the 
box canyon) , but are believed to hold back effectively the deep ground 
waters. The rock floor of the basins is likewise believed to be suffici- 
ently impervious to prevent the escape of ground water downward 
and out of the basins. 

The lake beds occupy the middle parts of the basins and extend 
far up on the sides, blanketing the Gila conglomerate to elevations 
several hundred feet above the river valleys. On the whole they 
seem to be an effective artesian cover, comparatively free from 
fractures and sufficiently impervious in themselves to prevent, at 

1 U. S. Geol. Survey Fifth Ann. Rept., pp. 134-135, 1885. 



SAN CARLOS INDIAN RESERVATION, ARIZ. 25 

least in part, the upward escape of water imprisoned beneath them. 
^Vlong the north side of the Gihx Valley, opposite Navajo Bill Point 
and at several other places farther east, small springs issue near the 
base of the bluffs. A group of springs occurs in the large arroyo 
wliich entei's the Gila from the north opposite Bylas siding. There 
is another spring in Kelly Wash, on the south side of the basin, 2 
miles southeast of San Carlos. (See PI. II.) If these springs repre- 
sent leakage from the artesian reservoir, as seems probable, the 
lake beds are not perfectly water-tight, but apparently the amount 
of water lost in this way is not great. At a number of places there 
are also evidences of a possible disturbance of the artesian cover, 
as indicated by lava intrusions and slight folding and faulting. 

In the Gila Basin favorable artesian conditions exist along the 
north side of the basin for 15 miles from the east boundary of the 
reservation to a point 8 miles east of the Triplets. Farther west the 
Gila conglomerate is not exposed and consequently the artesian 
prospects are not so good. On the south side of the Gila Basin 
favorable artesian conditions are found for a distance of 20 miles 
below Bylas and a point 4 miles east of the box canyon. 

In the San Carlos Basin artesian structure exists along the west 
side for 5 miles northward from the box canyon. Beyond that 
point the structure may be less favorable on account of possible 
serious disarrangements of the strata as a result of volcanic disturb- 
ances, which are indicated by numerous lava flows. On the east side 
the absence of outcrops of the Gila conglomerate makes conditions 
mifavorable. 

As the structure is favorable to artesian conditions on one or both 
sides of the Gila Basm between the east boimdary of the reservation 
and San Carlos, there are prospects that artesian water can be 
obtained in the river valley between these points by drilling through 
the recent alluvium and lake beds into the Gila conglomerate. 

As the structm-e is favorable to artesian conditions on the west 
side of the San Carlos Basin for 5 miles north from the box canyon, 
there are also prospects that artesian water can be obtained in the 
river valley from San Carlos north to the new San Carlos steel bridge. 
All this part of the valley, however, is inside the proposed reservoir 
site. In the part of the San Carlos Valley above the steel bridge 
conditions do not appear to be favorable for obtaining an artesian 
supply- 
According to the writer's estimates, based entirely on the probable 
relative positions of the formations as represented graphically in the 
cross sections in Plate II, the average thickness of the lake beds near 
the middle parts of the basins does not exceed 700 feet. However, 
as no complete sections are exposed, this estimate may be much too 
low. As the lake beds were laid down on an eroded and somewhat 



26 CONTRIBUTIONS TO HYDROLOGY OF UNITED STATES, 1919. 

hilly surface, their thickness probably varies from place to place. In 
some places it may be necessary to drill 1,000 or even 1,500 feet to 
reach the Gila conglomerate, and as much as 2,000 feet to penetrate 
the conglomerate deep enough to make a conclusive test. 

It is impossible from data obtained in a geologic investigation to 
predict definitely the presence or absence of artesian water, for the 
reason that unfavorable conditions may exist underground which 
do not appear at the surface. However, the investigation that has 
been made shows that the conditions, in so far as they can be observed, 
are sufficiently favorable to warrant the drilling of a test well. 

As no wells have been drilled into the Gila conglomerate, the quality 
of the water which it contains is not known. The source of the water 
is the rain on the outcrop and the run-off from the hard igneous and 
sedimentary rocks of the mountains above. The water as it enters 
the Gila conglomerate is therefore probably only moderately mineral- 
ized. In passing downward to lower levels through the conglomerate 
it dissolves more or less mineral matter, but, to judge from the char- 
acter of the materials in this formation as revealed in its outcrops, 
the amount of soluble matter is not large. There may, however, 
be buried saline beds along the axes of the valleys. In view of the 
source of the water contained in the Gila conglomerate and the 
character of the formation, there is reason to believe that the water 
is good enough for use. 

SUMMARY AND CONCIiUSIONS. 

1. The part of the Gila Valley within the reservation and outside 
of the proposed reservoir site contains about 4,595 acres of arable 
land. In 1913 only 421 acres, or less than 10 per cent of this arable 
land, was irrigated and farmed. 

2. The San Carlos Valley, all of which lies within the reservation, 
contains 1,840 acres of arable land above the proposed reservoir site. 
In 1913, 538 acres, or a little more than 30 per cent, of this arable land 
was irrigated and farmed. 

3. On account of the lack of sufficient water in Gila and San Carlos 
rivers during a certain period in summer when irrigation is most 
needed and on account of the difficulty of maintaining diversion dams 
and canals, the system of irrigation in 1914 was inadequate. 

4. In the river valleys water in sufficient quantities for irrigation 
can probably be obtained by pumping from shallow wells in the 
alluvium. 

5. The principal source of the water in the vaUey alluvium is beheved 
to be seepage from the rivers. Consequently the largest yields may 
be expected from wells near the river channels. 



SAN t'ARLOS INDIAN RESERVATION, ARIZ. 27 

6. In 1913 the cost of irrigating under the present system was $1.34 
an acre. Tlie cost of pumped well water would probably bo higher. 

7. The watere from shallow wells in the Gila Valley are heavily 
mineralized. They are so high in chlorine, which is one of the con- 
stituents of common salt, that they are of doubtful value for in-igation, 
and if used contmuously they would require extraordinary precau- 
tions to prevent an excessive accumulation of alkali in the soil. 

8. The shallow ground waters in the San Carlos Valley are believed 
to be better than those of the Gila Valley and comparable to the water 
from Gila River, which is now successfully used for irrigatioTi. 

9. Final judgment on the suitability of the shallow gi'ound waters 
for irrigation should be deferred until their effect on crops has been 
determined by actual experiment. 

10. To the extent that the shallow gi'ound waters are found to be 
good enough for irrigation they can be advantageously used on the 
tracts already under cultivation to supplement the surface-water 
supply and on arable tracts that lie above the ditches. 

11. In the Gila Basin structure favorable to artesian conditions 
exists on one or both sides of the valley between the east boundary of 
the reservation and San Carlos, and it is believed that artesian water 
can be obtained in the river valley between these points. 

12. In the San Carlos Basin structure favorable to artesian condi- 
tions exists only on the west side adjacent to that part of the valley 
included within the proposed reservoir. 

13. To test the water-bearing possibilities of the Gila conglomerate 
it will be necessary to drill through the Recent alluvium and the lake 
beds, which, according to the writer's estimates, have an average thick- 
ness below the river valleys of not more than 700 feet. In some places 
it may be necessary to drill 1,000 to 2,000 feet to test the existence of 
water-bearing beds. 

14. The structm-e appears most favorable on the south side of the 
Gila Basin, west of Bylas. A good location for a test well would be 
on Dewey Flat or on the 180-acre tract of arable land 1 mile east of 
Dewey Flat. 

15. There is no direct information as to the quality of the water in 
the Gila conglomerate, but it is probably good enough to be used for 
irrigation. 

16. Unfavorable conditions may exist undergi'omid that will make 
it impossible to obtain artesian wells, but the conditions as observed 
at the surface are sufficiently favorable to warrant the drilling of a 
test weU. 

o 



L 



p 



L 




LIBRARY OF CONGRESS 



029 708 306 5 1 




